Research program overview
Our research team seeks to characterize the quantity, quality and function of organic matter in surface soils from various ecosystems.
The interactions between organic and mineral materials are a fundamental feature of soils, differentiating them from geologic parent materials. Soil is primarily a mineral matrix (except in organic soils such as peat), but receives inputs of organic matter from various natural sources such as leaf litter and roots, or from various human sources such as manure or compost. As these organic materials are decomposed by soil animals and microorganisms (fungi and bacteria), it is physically and biochemically transformed into soil organic matter that is stabilized by interactions with soil minerals. Interactions between organic matter and soil mineral surfaces occur at the nano- to micro-scale, but their impacts are felt up to the global scale.
1500-2000 billion metric tons of carbon are stored in the top meter of the Earth’s soils, making it the largest of the active terrestrial carbon pools. Although soil organic carbon is essential to both soil fertility and global carbon budgets, the size of the global soil carbon pool has declined by 50-70% in the past 150 years due to land use changes. These historic losses now represent an opportunity to enhance carbon storage through conservation practices that promote soil carbon sequestration and fertility in croplands, rangelands and forests. For these reasons, soil organic carbon has become an object of considerable scientific interest.
We use biological, chemical and physical methods to characterize the organic matter in soils to answer questions about how long we can expect it to stay there, or how microbes process it into CO2 and other greenhouse gases. We have developed a set of techniques to study soil organic matter using ramped combustion. While slowly heating and burning the organic matter, we measure mass loss, heat flux and the evolved gases to related its thermal stability to its stability against decomposition in the environment.